Tube tester



Dec. 2-7, 1938. H. P. ANLY 2,141,479

-TUBE TESTER Filed April 13, 1956 Patented Dec. 27, 1938 UNITED STATESPATENT OFFICE TUBE TESTER Harold P. Manly, Niles Center, Ill.

Application April 13, 1936, Serial No. 74,104

4 Claims. (Cl. 250-27) The invention relates to tube testers for test- Asignal circuit 2| is arranged as shown to ing electronic tubes and hasfor its primary derive its current from the section 22 of the object theprovision of an improved tube tester transformer. The circuit 2| isdivided, as shown, of the character indicated which is of simple intotwo shunt circuits, each including one of the and economicalconstruction and highly efficient signal lights 23 and 24. Preferablythe signal 5 in use. light 23 is a, red light to indicate a defective orAnother object of the invention is the provision unsatisfactory tube,and the light 24 is a green of a tube tester of the character indicatedarlight to indicate a good or satisfactory tube. ranged with visiblesignals incorporated therein The lights 23 and 24 are connected as shownand so constructed and arranged that material with segmental electriccontacts 25 and 26 ar- 1 variations in the qualities of such tubes willbe ranged as shown in circumferential relation with visibly indicatedthereby. a gap 21 between them. A second rocker switch- Other objectswill appear hereinafter. arm 28 is mounted on the shaft 20 to cooperateThe invention consists in the combinations and as indicated with thecontacts 25 and 26 and is arrangements of parts hereinafter describedand in turn connected with the circuit 2|. claimed. In testing a tube,the tube to be tested is in- The invention will be best understood byreferserted in the circuit Ill with the switch-arm 28 ence to theaccompanying drawing forming a adjusted to a position in registrationwith the part of this specification, and in which gap 2'! and theswitch-arm l9 in the dotted line Fig. 1 is a diagrammatic viewillustrating a position as indicated in Fig. 1. The arrangetube testerembodying the invention; ment is such that under such circumstances, if

2 a similar view of a portion of said tester the inserted tube H isnormal or average, there but showing a slight modification or additionwill be no deviation of the needle or pointer l3.

thereto; and But suppose, however, that the inserted tube is Fig. 3 aview similar to Fig. 1 but showing a defective or unsatisfactory, theflow of current still further modification. is accordingly reduced tosuch extent as to cause The embodiment of the invention illustrateddeviation of the needle or pointer I3 to the dotted in Fig. 1 comprisesa testing circuit I0 including line position indicated in Fig. 1. anelectronic tube H, and a current flow indi- By manipulating the rockershaft 20, the re- 30 cator or meter |2 having an indicator arrow l3.sistance of the resistor I8 is increased until the 30 The tube filamentor cathode I4 receives current arrow or indicator I3 is returned to itscentral, from section |5 of a transformer, as indicated, normal fullline position indicated in Fig. 1. arranged to serve as a source ofcurrent for the Such manipulation of the switch-arm IE! to indifferentcircuits, transformer section l6 furnishcrease such resistancenecessitates the correing a flow of current passing through .the tubespending rocking of the shaft 20 and the switch- 35 plate and theindicator l2, as will be readily arm 28,thereby carrying the switch-arm28 away understood. from the gap 21 and onto the contact 25. ThisAssociated with the'circuit I0 is a shunt circuit causes excitation ofthe red light 23, thereby at H including an adjustable resistor |8controlled once flashing a visible readily noticed and in- 40 by arocker contact arm IS on a rocker shaft 20. dicative signal indicatingthat the tube in ques- 50 As will be readily understood, the positionastion is bad or unsatisfactory. If a tube better sumed by the arrow orpointer .-|3 of the indicator than average is inserted, the deviation ofthe I2 dependsupon the amount of current flowing needle or pointer I3will be in the opposite directhrough the tube and on the shuntresistance, tion, thus necessitating opposite adjustment of whichresistance is in turn determined by the the switch-arm ill to bring saidneedle or pointer 4* position of the switch-arm l9 relatively to theback to normal, central position. Such adjustresistor I8. If it isdesired to increase the ,pronient will carry the switch-arm 28 onto theconportion of the tube current which flows through tact 2'6, therebyflashing the green light 26 to V the indicator, the resistance of theresistor will indicate that the tube is above normal and satisbeincreased, and if it is desired to decrease the factory. By varying theposition of the gap 21 50 flow of such current through the indicator,the between the contacts 25 and 26, the point of resistance of theresistor will be decreased. In eificiency at which the tube would beindicated this manner the position of the arrow or pointer assatisfactory or unsatisfactory may be varied |3 of the indicator |2 maybeadjustedas desired as desired. Thus a radio or electronic tube withinthe limits of-the apparatus. tester is provided which is of simple andeco- E5 cated in Fig. 2. Here a second shunt circuit 29 is connectedwith circuit In in shunt with the indicator l2 and equipped with anadjustable resistor 30 and an adjusting contact arm 3|. A source ofcurrent 32 is also included in the shunt circuit 29 and by means ofwhich auxiliary current may be passed through the indicator I 3 from thesource 32, in addition-to the normal current flowing through the tubeand meter. This auxiliary current may be adjusted so that, with normaltube current, the sum of the normal current and the auxiliary currentwill bring the meter arrow to the central, normal position. This wouldprovide some current flowing through the indicator at all times. Werethe tube to be completely defective so that no tube current would flow,the auxiliary current still would allow-of the bringing of the indicatorl3 to the central normal position when the switch-arm i9 is adjusted asabove described. The auxiliary current source would then provide acurrent flow whose amount would depend upon adjustment of the resistorcator to bring the arrow l 3 to the central, normal position. Thus theapparatus may be adjusted to permit of the testing of a wide Variety oftypes of radio or electronic tubes.

In Fig. 3 I have illustrated 'a testing apparatus in which a change ofvoltage rather than of current is utilized in making the test in testingtubes, such as electronic tubes having a control element such as a grid.In this instance the testing circuit I0 is arranged for the insertion ofan electronic tube 33 containing a grid 34 asva control element. A wire35 connects the grid 34 with a rocker contact arm 36 on a rocker shaft31. The contact arm 36 cooperates with the resistor 38 connected asshown in a second testing circuit 39 which includes a battery 40 as asource of current. The circuit 39 is also connected by the wire 4| withthe cathode I4 of the tube 33.

The second rocker contact arm 42 is carried by the shaft 31 andcooperates with segmental contacts 43 and 44 arranged as indicated witha gap 45 between them. The contacts 43 and 44 are included in thecircuit 2| with the signal lights 23 and 24. V

In use the contact arm 36'is positioned adjacent the right hand end ofthe resistor 38, and we will assume that upon insertion of the tube 33in the circuit H] the indicating needle l3 assumes the dotted lineposition shown and that in order to bring the needle I3 back'to itscentral or normal position it is found necessary to swing the contactarm 36 to its full line position. Obviously such swinging of the contactarm 36 will cause a corresponding difference in voltage between the grid34 and cathode [4 of the tube 33 which will cause a correspondingincrease in the flow of current through the indicator l2 depending uponthe efficiency of the tube 33, the smaller the voltage change necessaryto cause the required increase in current flow, the greater theefliciency of the tube, and vice versa. The length of the contact 44effect the required current increase.

is made such that it will remain in contact with the rocker arm 42 foran extent of movement corresponding with a permissible voltage change toAs long as the contact arm 42 remains in contact with the member 44, thegreen light 24 will be lighted, thereby indicating that the tube beingtested is satisfactory. However, if a greater voltage change is requiredto cause the necessary increase in flow of current through the indicatorand tube, the arm 42 will pass across the gap 45 onto the contact member43, thereby lighting the red light 23 and thereby indicating that thetube being tested is unsatisfactory. The green light will go out as theindicator arm 42 passes the gap 45 indicating that the tube is on theborder line between a satisfactory and an unsatisfactory tube. In thisway electronic tubes having a grid control element or the like may alsobe readily tested for efficiency and. the eificiency thereof visuallyportrayed by the green and red lights 24 and 23 respectively. 7

While I have illustrated and described the preferred forms ofconstruction for carrying the invention into effect, these are capableof variation and modification without departing from the spirit of theinvention. I therefore do not wish to be limited to the precise detailsdisclosed, but

desire to avail myself of such variations and modifications as fallwithin the scope of the appended claims.

I claim:

1. A tube tester comprising a tube testing circuit including a currentindicator and means for inserting a tube to be tested therein; anadjustable resistor'in shunt with said indicator; an adjustable contactfor adjusting said resistor to vary the current flowing through saidindicator;

,two signaling devices; and an operative mechanical connection betweensaid contact and said si naling devices arranged to operate one deviceupon shifting of said contact in one direction and the other upon suchshifting in the other direction.

2. A tube tester comprising a tube testing circuit including a currentindicator and means for inserting a tube to be tested therein; anadjustable resistor in shunt with said indicator; a rocker shaftcarrying an adjustable contact for adjusting said resistor to vary thecurrent flowing through said indicator; a signal circuit including twosignaling devices; a second contact on said rocker shaft; and twosegmental electric contacts in said signal circuit arranged with a gapbetween them and one connected with one of said signal devices and theother with the other signal device, said second contact co-operatingwith said segmental contacts.

3. A tube tester comprising a tube testing circuit including a currentindicator and mean s for inserting a tube to be tested therein; anadjustable resistor in shunt'with said indicator; an adjustable contactfor adjusting said resistor to vary the current flowing through saidindicator; two signaling devices; an operative mechanical connectionbetween said contact and said signaling devices arranged to operate onedevice upon shifting of said contact in one direction and the other uponsuch shifting inthe other direction; a second adjustable resistor inshunt with said indicator; and a source. of current in the shunt of saidsecond'resistor. V

4. A tube tester comprising a. tube testing circuit includinga-currentindicator and means for inserting a tube to be' tested-therein; anadjustable resistor in shunt with said indicator; a rocker shaftcarrying an adjustable contact for adjusting said resistor to vary thecurrent flowing through said indicator; a signal circuit including twosignaling devices; a second contact on said rocker shaft; two segmentalelectric contacts in said signal circuit arranged with a gap betweenthem and one connected with one of said signal" devices and the otherwith the other signal device, said second contact co-operating with saidsegmental contacts; a second adjustable resistor in shunt with saidindicator; and a source of current in the shunt of said second resistor.

HAROLD P. MANLY.

